1. Field of the Invention
The present invention relates to an illuminance sensing head structure, and more particularly to an illuminance sensing head structure that may correct the cosine effect of the optics.
2. Description of the Related Art
A first conventional illuminance sensing head in accordance with the prior art shown in FIG. 1 comprises a housing 3, a convex diffusion plate 1 mounted in the housing 3 and having an outer periphery provided with a positioning ring 11, a fixing plate 2 secured on the housing 3 by a screw member 4 and having an annular insertion groove 21 securing the positioning ring 11 of the diffusion plate 1. However, the periphery of the diffusion plate 1 is pressed by the fixing plate 2, so that it is unable to detect the effect of the side directed light, and so that the light source is not even, thereby limiting the cosine effect of the optics.
A second conventional illuminance sensing head in accordance with the prior art shown in FIG. 2 comprises a housing 3, a flat diffusion plate 5 mounted in the housing 3, a fixing plate 2 secured on the housing 3 by a screw member 4 and having an annular insertion groove 21 securing the periphery of the diffusion plate 5. However, the flat diffusion plate 5 is stopped by the thickness of the fixing plate 2, so that the amount of the incident light is not enough, and so that the light source is not even, thereby limiting the cosine effect of the optics.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional illuminance sensing head.
The primary objective of the present invention is to provide an illuminance sensing head structure which includes a diffusion plate provided with an enclosure, thereby efficiently correcting the cosine effect of the optics, and thereby enhancing the testing precision of simulating human eyes to detect the illuminance intensity.
In accordance with the present invention, there is provided an illuminance sensing head structure, comprising a housing, a light detector, a positioning member, a first color light filtering plate, a second color light filtering plate, and a diffusion plate;
wherein, the housing is integrally formed by black opaque plastic material, and has a top face recessed with a square plate receiving slot for receiving the first color light filtering plate and the second color light filtering plate, the plate receiving slot has a center recessed with a rectangular receiving chamber which is formed with an oblique side, for receiving the light detector which has an oblique side, one side of the plate receiving slot has a mediate section formed with a member receiving space, for receiving the positioning member;
wherein, the plate receiving slot of the housing has an outer edge provided with multiple rod insertion holes;
the diffusion plate is a plate having a high diffusivity, and has an enclosure, the diffusion plate has a bottom formed with multiple insertion rods each inserted and secured into the rod insertion hole of the housing, each insertion rod has a rod diameter close fit in the hole diameter of each rod insertion hole.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.